Windows 3.0
Windows 3.0, a graphical environment, is the third major release of Microsoft Windows, and was released on May 22, 1990. It became the first widely successful version of Windows and a rival to Apple Macintosh and the Commodore Amiga on the graphical user interface (GUI) front. It was followed by Windows 3.1. Windows 3.0 originated in 1989 when David Weise and Murray Sargent independently decided to develop a protected mode Windows as an experiment. They cobbled together a rough prototype and presented it to company executives, who were impressed enough to approve it as an official project. Real and Protected mode Although Windows 3.0 wasn't the first version that could run in Protected mode (which was split into two modes, see below), it was the first "universal release" that could run in all three modes. Windows 2.x versions could only run in the mode they were released for, i.e. regular 2.x in Real mode, 2.x 286 in Real and Standard modes, and 2.x 386 in Real and 386 Enhanced modes. The Protected mode was split into two separate modes: "Standard mode" (the 16-bit 286 Protected mode available on the Intel 286 and clones) and "386 Enhanced mode" (32-bit 386 Protected mode available with Intel 386 and clones). The Multimedia Extensions were not available in Real Mode. Windows 3.0 has a problem starting in 386 Enhanced mode in Microsoft Virtual PC 2004/2007 due to conflicts between Windows 3.0's 386 memory management and Virtual PC's video BIOS. A fix for this issue is described in this guide. The only leaked beta build (3.00.55) doesn't have this problem. System requirements *8086/8088 processor or better *384 KB of free conventional memory (real mode), 1 MB (Standard Mode), or 2 MB (Enhanced Mode) *Hard disk with 6-7 MB of free space *CGA, EGA, MCGA, VGA, Hercules, 8514/A or XGA graphics and an appropriate and compatible monitor *MS-DOS version 3.1 or higher Also, a Microsoft-compatible mouse is recommended. Memory modes Windows 3.0 was the only version of Windows that could be run in three different memory modes: *Real mode, intended for older computers with a CPU below Intel 80286, and corresponding to its real mode; *Standard mode, intended for computers with an 80286 processor, and corresponding to its protected mode; *386 Enhanced mode, intended for newer computers with an Intel 80386 processor or above, and corresponding to its protected mode and virtual 8086 mode. Real mode primarily existed as a way to run Windows 2.x applications. It was removed in Windows 3.1x. Almost all applications designed for Windows 3.0 had to be run in standard or 386 enhanced modes. (Microsoft Word 1.x and Excel 2.x would work in real mode as they were actually designed for Windows 2.x). However, it was necessary to load Windows 3.0 in real mode to run SWAPFILE.EXE, which allowed users to change virtual memory settings. Officially, Microsoft stated that an 8Mhz turbo 8086 was the minimum CPU needed to run Windows 3.0. It could be run on 4.77 MHz 8088 machines, but performance was so slow as to render the OS almost unusable. Up to 4 MB of EMS memory is supported in real mode. Standard mode was used most often as its requirements were more in-line with an average PC of that era — an 80286 processor with at least 1 MB of memory. Since some PCs (notably Compaqs) did not place extended memory at the 1 MB line and instead left a hole between the end of conventional memory and the start of XMS, Windows could not work on them except in real mode. Standard mode was still widely used on 386 PCs as many only had 1-2 MB of memory and used the 386SX chip (a cut-down version with a 16-bit data bus), so they could not run Enhanced mode well. 386 Enhanced mode was a 32-bit virtual machine that ran a copy of 16-bit Standard mode, and multiple copies of MS-DOS in virtual 8086 mode. In 286 mode, the CPU temporarily switches back into real mode when a DOS application is run, thus they cannot be windowed or switched into the background, and all Windows processes are suspended while the DOS application is in use. 386 enhanced mode by comparison uses virtual 8086 mode to allow multiple DOS programs to run (each DOS session takes 1 MB of memory) along with being windowed and allowing multitasking to continue. Virtual memory support allows the user to employ the hard disk as a temporary storage space if applications use more memory than exists in the system. Normally, Windows will start in the highest operating mode the computer can use, but the user may force it into lower modes by typing WIN /R or WIN /S at the DOS command prompt. If the user selects an operating mode that cannot be used due to lack of RAM or CPU support, Windows merely boots into the next lowest one.